1906.] 



Spraying Mixtures. 



663 



leaf-eating caterpillars and to check scab in apples and pears or 

 leaf-blight in plums, is cone when the foliage is better able to 

 withstand the effect of Paris green than it is in its half-developed 

 stage. It is much to be regretted, however, that no fungicide 

 has been discovered which will mix harmlessly with lead arsenate. 

 As there is none available, it may be suggested that, in spraying 

 against the Codlin moth, just after the blossom has fallen from 

 apple trees, arsenate of lead alone should be used. Then, if scab 

 be apprehended, Bordeaux mixture can be applied a few days 

 later. 



Where Codlin moth is not troublesome, a combination, which 

 is at once about the most effective against the apple-sucker and 

 the aphis and a check to scab in apples and pears and leaf- 

 blight in plums, is fortunately not liable to cause decomposition. 

 This is a mixture of quassia, soft soap, and potassium sulphide. 

 As the two former ingredients, liberally used, proved strong 

 enough to kill the saw-fly caterpillar on gooseberry bushes last 

 season, completely clearing the infested bushes, they would be 

 equally effective against other leaf-eating caterpillars, at least if 

 the pests were sprayed when young. This mixture would not 

 poison the food of the pests, as Paris green or lead arsenate 

 does, and therefore it would act only upon broods existing at 

 the time of spraying. But in many plantations apple-suckers 

 and aphides on apple trees, and the latter on plums, are much 

 more destructive than any caterpillars, and in such cases this 

 unobjectionable mixture is strongly to be recommended. The 

 strength which proved effective against saw-fly caterpillars was 

 one of 12 lb. of quassia chips and 12 lb. of soft soap to 100 

 gallons of water. The chips were boiled for an hour in twelve 

 gallons of water with half the soft soap, and after the liquid had 

 been drawn off, the same chips were boiled again with the other 

 half of the soft soap, and the two decoctions were mixed and 

 diluted. To this mixture 6 lb. of potassium sulphide, , after 

 being separately dissolved, should be added as a fungicide. If 

 applied just before the leaf-buds on apples and plums open, it 

 may do much to prevent apple-suckers and aphides from har- 

 bouring on the trees where they are hatched, and possibly to 

 check scab and leaf-blight. The operation may be repeated 

 after the blossom has fallen for the same purposes. The two 



